The invention relates to a hydraulic fluid reservoir cap having a spring that applies a force to compress a seal between the cap and a reservoir filler neck and to the reduction of a initial cap mounting torque.
Hydraulic fluid reservoirs have openings for checking the hydraulic fluid level and for adding hydraulic fluid. It is essential that the reservoir openings be closed to eliminate hydraulic fluid contamination. Contaminants can damage hydraulic system components such as pumps, valves and actuators. The sealing of reservoir openings is particularly important for reservoirs on vehicles, such as power steering reservoirs, due to their operating conditions. Such reservoirs are subjected to moisture, dust, abrasives, and various chemicals.
A hydraulic reservoir cap, that is currently used on automotive vehicle reservoirs, has a cap with a cap stick. A gasket is telescopically received on the cap stick. A cup member with a pair of radially extending ears, is telescopically and non-rotatably received on the cap stick. A coiled compression spring has one end seated on the cup member and the other end seated on a ledge on the cap stick so that the compression spring urges the cup toward the gasket. When the reservoir cap is mounted on a reservoir opening neck, in a closed position, the cup ears contact an interior ramp surface on the reservoir opening neck, the gasket contacts an exterior surface of the reservoir opening neck and the gasket is compressed between the reservoir opening neck and the gasket seat on the cap stick by the compression spring. As the gasket wears the compression spring maintains a seal. The reservoir cap is rotated about 125xc2x0 in one direction to close the reservoir opening neck and in the opposite direction to open the reservoir opening neck. A torque of about 2.3 Nm is required to rotate the reservior cap to a closed position or to an open position. Most individuals can easily rotate the closure cap to an open or to a close position without difficulty.
During assembly of hydraulic reservoirs, and prior to shipment to vehicle assembly lines, a reservoir cap is placed on a hydraulic reservoir and rotated to a closed position to keep contaminants out of the reservoir. A person that installs several thousand of the reservoir caps on the reservoirs during an eight-hour shift will likely find a torque of about 2.3 Nm tiring.
A tool which provides leverage and reduces the force required to rotate a closure cap to a closed position has been tried. Such a tool reduces the force required to produce a torque of 2.3 Nm and reduces the chance of a repetitive stress injury. Unfortunately the tool substantially increases the time required to install a reservoir cap. The increased time required to install a reservoir cap using a tool substantially reduces the number of reservoir caps that can be installed in eight hours and increases the cost of each of reservoir produced.
The reservoir cap for a fluid reservoir includes a cap plate having a cap gasket surface. A cap stick has a base portion that is integral with the cap plate. The cap stick has a stick axis that is perpendicular to the cap gasket surface. A primary flat surface on the cap stick is parallel to the stick axis and extends axially away from the cap gasket surface. A shelf on the cap stick is axially spaced from and parallel with the cap gasket surface. A gasket is telescopically received on the cap stick and in contact with the cap gasket surface. A cup has two radially extending ears and a central bore with a flat cup bore surface. The central bore telescopically receives the cap stick. A spring is in engagement with the cup and the cap stick and urges the cup toward the cap gasket surface. The cup is rotatable relative to the cap stick into engagement with the shelf to hold the cup in a preliminary position. The cup is rotatable out of engagement with the shelf to free the cup to be moved toward the cap gasket surface and into a working position by the spring.